Katie Lowes may battle psoriasis, but she isn’t allowing the diagnosis to dictate her life.

At the age of 28, the Scandal star was living out “the best year” of her life. “I was engaged to my then-boyfriend, now-husband. I booked Scandal, which was the biggest acting job I had ever booked,” she exclusively tells PEOPLE.

But the stress that accompanied the excitement seven years ago compounded, and sparked her psoriasis, which started at the base of her head and all down the back of her neck and spread to the upper part of her back and behind the ears.

“The stress really from the year of wedding planning and just having a lot of eyes on me from being on a show that people were watching — and I’d never gone through something like that before — triggered psoriasis outbreaks to start happening and getting worse and worse and worse,” says Lowes, 35.

Although she was a star on the highly-rated ABC drama series, Lowes admits she felt alone and self-conscious because of the skin disease.

“I know that for myself, I felt alone for a really long time. And I also felt incredibly embarrassed and ashamed, especially in Hollywood where there’s such a pressure to look and be perfect. I’m on a television show and I’m in hair and makeup trailer getting ready and people are looking at me up close and personal at work, on the red carpet,” says Lowes. “And even in my day-to-day life that’s more similar to other people — you know, dates with my husband and vacations with my husband where I’m in bathing suits and my skin is out and I’m having a flair-up.”

She adds: “I felt the pressure, too. At the beginning especially, I was like ‘Oh my gosh, I don’t want anyone to ever know. This is so embarrassing and so not sexy. What happens if I get hired to play a sexy role?’ ”

Despite working day in and out with the Scandal cast for the past five years, Lowes reveals that she kept her diagnosis under wraps from her costars, and only told hair and makeup crew on-set about her diagnosis. “It was such an embarrassing time where I also — because I was so new to having a hotshot Hollywood job — you just feel like, ‘Oh gosh, I don’t want anyone to know.’ I kept it on the quiet,” she says. “The only people I really told at Scandal were the hair and makeup people because they have to deal closely with how I look on camera. So I’ll be curious to see what the Scandal cast says.”

Courtesy Tonic CLC

Though Lowes was at the highest point in both her personal and professional life, she says the moment she said “enough is enough” was when she canceled an engagement photo shoot as a result of a terrible flair-up.

“I didn’t feel like I had an appropriate outfit to wear. I’d have to wear my hair down, I’d have to wear a scarf and dress couldn’t be backless and all this stuff. I canceled it because I was feeling terrible in my own skin and that was kind of the straw that broke the camel’s back,” she tells PEOPLE.

Finally, Lowes decided to take control. After visiting numerous doctors in the Los Angeles area, the actress found the treatments that work for her through many “trial and errors.”

Now, the ABC star is confident in her skin and is thankful for her husband, Adam Shapiro, her family and support system for helping get her through the difficult time. To encourage the 7.5 million Americans battling the disease, Lowes has partnered with Janssen Biotech Inc. and the National Psoriasis Foundation for Psoriasis: The Inside Story, which aims to empower those living with psoriasis to take action and live their fullest life.

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“I’m at a really good place with the disease personally,” says Lowes. “I’ve come to a place where I’ve managed the symptoms really well and come to a place where I feel mentally healthy. I almost feel like I’ve come to a side of it where I feel really strong and empowered that I was able to spend a bunch of years early on, like from 28-30, really working with finding the doctor that would be the best fit for me. Finding a treatment after trying a bunch of different ones and not giving up and being my own best advocate to find a way that I can minimize these symptoms and live a day-to-day life that is not filled with embarrassment and shame.”

In addition to Lowes, other leading advocates are offering their personal perspectives and support on Psoriasis: The Inside Story, where visitors gain access to resources and support.

“If I can inspire even one person to push themselves to find a doctor that works for them, find a treatment that works for them, and to get their day-to-day life in a place that they can be proud of, then I will lay my head on the pillow with a big fat smile on it,” says Lowes.